The present invention relates to crystalline intermediate compounds useful in the synthesis of carbapenem antibiotics. The carbapenems derived from the present invention are useful against gram positive microorganisms, especially Methicillin resistant Staphylococcus aureus (MRSA), Methicillin resistant Staphylococcus epidermidis (MRSE), and Methicillin resistant coagulase negative Staphylococci (MRCNS). There is an increasing need for carbapenems effective against such pathogens, as well as intermediates which facilitate their production. The crystalline intermediates of the present invention thus facilitate an important contribution to therapy for treating infections caused by these difficult to control pathogens.